Optical Information Carrier

Abstract

An optical information carrier comprises a data layer for carrying the information, an outer surface for receiving a light beam for reading the information, and a transparent layer for transmitting the light beam to the data layer. The transparent layer comprises a pattern of physical damages for locally deforming the light beam. The physical damages are embedded in the transparent layer at a depth between the outer surface and the data layer. In the pattern of physical damages additional information is encoded. The additional information may be used for the purpose of copy protection.

1 . An optical information carrier ( 1 ) comprising:
 a data layer ( 4 ) for comprising information,   an outer surface ( 2 ) for receiving a light beam ( 7 ) for reading the information, and   a transparent layer ( 3 ) for transmitting the light beam ( 7 ) to the data layer ( 4 ), the transparent layer ( 3 ) comprising a pattern of deformations ( 6 ) of the transparent layer ( 3 ) for locally deforming the light beam ( 7 ), the pattern comprising additional information, the deformations ( 6 ) being embedded in the transparent layer ( 3 ) at a depth between the outer surface ( 2 ) and the data layer ( 4 ).   
   
   
       2 . An optical information carrier as claimed in  claim 1 , wherein at least part of the information is locked and the pattern constitutes a key for unlocking at least part of the locked information. 
   
   
       3 . An optical information carrier as claimed in  claim 2 , wherein the information comprises a software application which, when run, queries the key. 
   
   
       4 . An optical information carrier as claimed in  claim 1 , wherein the pattern comprises deformations embedded in the transparent layer between the outer surface and the data layer at at least two different depths. 
   
   
       5 . An optical information carrier as claimed in  claim 4 , comprising multiple data layers and multiple transparent layers, the deformations being embedded in at least one of the transparent layers between the outer surface and at least one of the data layers. 
   
   
       6 . An optical information carrier as claimed in  claim 1 , wherein the deformations are realized as different types of deformations, each type of deformations locally deforming the light beam differently. 
   
   
       7 . A device for reading information from an optical information carrier as claimed in  claim 1 , the device comprising a light detecting unit for obtaining the information from the light beam, the light detecting unit being arranged for analyzing a light intensity distribution on the light detecting unit for detection of the embedded deformations. 
   
   
       8 . A device as claimed in  claim 7 , further comprising an automatic gain control unit and/or a focus error detection unit and/or a tracking error detection unit, at least one of said units being arranged for the detection of the embedded deformations. 
   
   
       9 . A method for manufacturing an optical information carrier as claimed in  claim 1 , comprising a step of embedding the pattern of deformations in the transparent layer of the information carrier, at a depth between the outer surface and the data layer. 
   
   
       10 . A method as claimed in  claim 9 , wherein the step of embedding the pattern of deformations comprises exposing the transparent layer via a mask to radiation from a radiation source for creating the deformations embedded in the transparent layer. 
   
   
       11 . A method as claimed in  claim 10 , wherein the mask comprises an array of micro lenses and the radiation source is a light source, the micro lenses being arranged for focussing the light source at specific depths in the transparent layer for creating the deformations in the transparent layer.